简介：用EXAFS方法研究了重金属Zn(Ⅱ)在δ-MnO2上吸附的微观结构及吸附机制。在pH5．50，0．1M硝酸钠介质中，吸附-解吸实验表明Zn(Ⅱ）在δ-MnO2上的吸附可逆性很高．EXAFS结果表明，δ-MnO2表面上吸附态Zn2+以六配位的水合离子八面体形式存在。八面体的水合Zn^2+离子与δ-MnO2的结构单元MnO6八面体通过共用O原子结合，形成角-角结合的弱吸附．Zn-O平均原子间距为2．071A，Zn-Mn平均原子间距为3．528A。同一条等温线上随着吸附量增加，角-角结合的弱吸附形式基本上没有变化。Zn(Ⅱ)在δ-MnO2上较高的吸附可逆性是由于吸附态Zn(Ⅱ)与δ-MnO2以弱吸附的角-角形式结合所导致的。

简介：用延展X光吸收精细结构光谱(EXAFS)研究了重金属Zn(Ⅱ)在水锰矿(Y-MnOOH)上吸附产物的微观结构及其吸附机制。结果表明，Zn(Ⅱ)-水锰矿体系中(pH7．5，0．1MNaNO3介质，25℃)，Zn(Ⅱ)离子主要是通过Zn-O键结合到水锰矿固体表面上的，平均Zn-O原子间距为1．9984-0．010A(n=3)。同时，第二配位层(Zn-Mn相互作用)的EXAFS图谱解新证明存在两个典型的Zn-Mn原子间距，即R1=3．08±0．024A(n=3)和R2=3．54±0．018A(n=3)。这两个Zn-Mn原子距分别对应于水锰矿结构单元MnO6八面体与Zn水合离子ZnO多面体结合的两种方式，即边-边结合与角-角结合。边-边结合是较强的吸附位，Zn-Mn原子距较短(Rl=3．08A)，吸附较不可逆。角-角结合是较弱的吸附位，Zn-Mn原子距较长(R2=3．54A)，吸附较为可逆。宏观的吸附一解吸热力学实验表明Zn(Ⅱ)在水锰矿上的吸附是不可逆的，EXAFS结果指出这种不可逆性主要是由Zn水合离子中Zn0多面体与水锰矿结构单元MnO6八面体之间的边-边结合所导致的。

简介：Zn_(1-x)Cu_xOthinfilmsweresynthesizedbytheradiofrequency(RF)magnetronsputteringtechniqueusingaZnOtargetcontainingdifferentpiecesofsmallCu-chips.X-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)wereemployedtoanalyzethecrystallineandmicrostructureofthefihn,andX-rayphotoelectronspectroscopy(XPS)wasusedtoestablishthebondingcharacteristicsandoxidationstatesofcopperinsidetheZnOhost.Roomtemperature(RT)ferromagnetismwasobservedintheZn_(1-x)Cu_xOfilmsbyaQuantumDesignsuperconductingquantmninterferencedevice(SQUID)andthesaturationmagneticmomentofthefilmswasfoundtodecreasewiththeincreaseinCucontent.

简介：Thecomplexnatureoflaser-materialinteractioncausesnon-stoichiometricablationofalloysamples.Thisisattributedtomatrixeffect,whichreducesanalyzingcapability.Toaddressthisissue,theanalyticalperformanceofthreedifferentnormalizationmethods,namelynormalizationwithbackground,internalnormalizationandthreepointsmoothingtechniquesatdifferentparametersettingsisstudiedforquantificationofAgandZnbyLaserinducedbreakdownspectroscopy(LIBS).TheLIBSspectraoffiveknownconcentrationofsilverzincbinarycompositeshavebeeninvestigatedatvariouslaserirradiances(LIs).CalibrationcurvesforbothAg(I)line(4d^105s^2S1/2→4d^105p^2P1/2at338.28nm)andZn(I)line(4s5s^3S1→4s4p^3P2at481.053nm)havebeendeterminedatLIof5.86×10^10Wcm^-2.SlopesofthesecalibrationcurvesprovidethevaluationofmatrixeffectintheAg–Zncomposites.Withcarefulsamplepreparationandnormalizationaftersmoothingatoptimumparametersetting(OPS),theminimizationofsamplematrixeffecthasbeensuccessfullyachieved.AgoodlinearityhasbeenobtainedinAgandZncalibrationcurveatOPSwhennormalizedthewholeareaofspectrumaftersmoothingandtheobtainedcoefficientsofdeterminationvalueswereR^2=0.995and0.998closerto1.Theresultsofmatrixeffecthavebeenfurtherverifiedbyanalysisofplasmaparameters.BothplasmaparametersshowednochangewithvaryingconcentrationatOPS.However,athighconcentrationofAg,theobservedsignificantchangesinbothplasmaparametersatcommonparametersettingPS-1andPS-2werethegestureofmatrixeffect.Inourcase,thebetteranalyticalresultswereobtainedatsmoothingfunctionwithoptimizedparametersettingthatindicatesitismoreefficientthannormalizationwithbackgroundandinternalnormalizationmethod.